Author Topic: Ignition timing  (Read 2001 times)

Rob B

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Ignition timing
« on: November 05, 2014, 06:05:34 PM »
Does anyone have some good advice please for ignition timing with an advance strobe and indeed, is this even possible with a wasted spark system like on the H? If so, what should the advance curve look like (if the RITA has such a thing as a curve) and what should the maximum advance be at say 4,000 rpm? This is a subject I have been struggling with on the H for about thirty years now so it is probably about time to try and work out what I am doing wrong...

I do know one answer is to bin the RITA in favour of a flashy modern digital programmable system but when you consider the dismal carburation etc. etc. then that is probably a bit like polishing a turd.

Answers on a postcard please, or two :-)

Many thanks,

Robert
RB

1980 Jota - 1982 V1000 - 1985 SFC 1000
1993 907IE - 1995 Daytona Super III
1960 Perplexed Wife

Miti

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Re: Ignition timing
« Reply #1 on: November 05, 2014, 10:30:26 PM »
Hi Rob;

The biggest problem with the Lucas-Rita system is the way it's triggered... The "slack" twixt crank and camshafts means that it's almost impossible to set both cylinders exactly...  The error introduced tends to generate an advance curve that starts one side of ideal and drifts to the other side as revs increase...

There is some general info on the Rita Unit here and here.

The new digital systems use a trigger wheel connected directly to the crank, so it's easier to set both cylinders accurately and trust that the accuracy will remain constant across the rev range of the engine...

Mick's digital upgrade used a programmable unit manufactured by Gill Engine Controls

There have been a few changes to the static timing on the V1000, I would be very interested to know what the correct setting should be as I don't thnk my bike is running as well as it should be (poor starter and low mpg)  Runs much quieter than is used to though...

Jeff
1975 Triumph Trident 750 (New Project)
1980 Yamaha XS1100 (Midnight Special)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Reg'd 1985)
1982 Hesketh V1000 (Pre-Production Engine)

Dave Snr

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Re: Ignition timing
« Reply #2 on: November 06, 2014, 10:05:24 AM »
Hi Rob,

I've always used the setting given in the owners manual and in Mick's V1000 workshop Manual 1982 plus EN10 mods which Jeff has put on the website, which is 22 degrees BTDC at 3,000 rpm - the F marks on the Alternator.
Never had to alter it. When I did my 60k top end overhaul I put the adjustment back to the same position and when I checked it, it was spot on.
Just done a 75k cam chain tension and valve clearance check and again the timing didn't need adjusting.
Full advance is given as 34 degs at 4000+ rpm, but you'd have to rig a degree plate onto the alternator rotor.
In 2012 Andy Smith was investigating a programmable unit to replace the Rita and had Mick's curves from his ignition unit to copy. Don't know if he made much progress.
Dave H

MICK

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Re: Ignition timing
« Reply #3 on: November 06, 2014, 11:04:15 AM »
Hi Rob,
The Rita ignition system gets its advance curve from seeing the magnet earlier as the thing speeds up so it never stops advancing completely though the curve is flatter at the higher speed.
The mechanical drive does give a different advance to either cylinders but the advance curve crosses over with a maximum I have seen of 3 degrees so you cannot do much about it.
You are correct in your judgement on the benefits of really accurate timing on the standard V1000 but you do need to start the improvements somewhere and while its not possible now my biggest regret was that that the owners could not experience the benefit that a more sorted motor gives you. Its a bit of a surprise how good it can be.
The problem with the 22 degree timing advice is that it is in the most active part of the curve so a little error can give a big difference in the thing you are trying to achieve which is the correct timing on full load.
The 22 degree figure is to allow you to time the engine after a rebuild without revving the plot to death but the important figure is full advance.
One thing all should check is that the marks on the alternator are correct by finding TDC and checking the mark, then you should have two other marks at 22 and 34 degrees which you can check with a degree disc.
Another must is maintaining a small air gap on the reluctor which helps starting as it starts triggering at a lower speed.
Hope this helps.

Miti

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Re: Ignition timing
« Reply #4 on: November 06, 2014, 12:06:29 PM »
When checking the timing at full advance, be sure to have the following euipment to hand:

Rubber gloves (full arm length)
An umbrella (that you didn't want any more).
A set of good quality oilskins
5kg sack of "Sorbisil" oil absorbent granuals
A garage floor that was in dire need of lubrication.

The alternator rotor runs in the same oil as the primary drive/starter mech - there is a LOT of it..!!
When bringing the motor up to 3,000, the centrifugal force that the rotor applies to this oil is simply amazing... I had oil dripping from the garage roof beams..!!

I'll be making up a perspex dummy cover for my next adjustment efforts... It'll be worth the time, effort and cost in the oil savings alone!!  ;)

Jeff
« Last Edit: November 06, 2014, 06:18:28 PM by Miti »
1975 Triumph Trident 750 (New Project)
1980 Yamaha XS1100 (Midnight Special)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Reg'd 1985)
1982 Hesketh V1000 (Pre-Production Engine)

Rob B

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Re: Ignition timing
« Reply #5 on: November 06, 2014, 05:47:57 PM »
Brilliant!

Then I think my biggest problem is trying to use an "advance strobe" which is the type that has and advance/retard adjuster knob and just looks at the static timing mark. I will get hold of a straight forward strobe and, having checked that the marks are correct, then go with the 3,000 rpm one.

I will also take Jeff's advice and make a Perspex cover and maybe even put some clean oil in so that I can see through it.

The only thing from memory though is that my alternator rotor seems to have a whole load of marks on it so I need to find the right ones first.

Thanks to all.

Robert
RB

1980 Jota - 1982 V1000 - 1985 SFC 1000
1993 907IE - 1995 Daytona Super III
1960 Perplexed Wife

Miti

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Re: Ignition timing
« Reply #6 on: November 06, 2014, 06:40:58 PM »
Timing srobes with an adjustable advance are quite easy to use once you have the hang of it...

Two ways to do it:

  • Set the adjustment to 0o (Nil advance).  The strobe will now flash in "real time" and the timing marks will show the actual advance that the engine is running at.
  • Set the strobe adjustment to the desired advance (22o and/or 34o in our case) the strobe now "builds in" the pre-set advance, so the full advance that the engine is running at will show as 0o,and this will read as being at the "TDC" mark
.

Remember, all ignition advance/retard figures are measured against TDC, NOT the "F" mark.

The "F" mark gives the minimum or "static" advance and an adjustable strobe allows for adjustments to this and elsewhere in the rev-range, where appropriate marking isn't always given...

I've had one of these for some years now:



Not cheap, but good quality and easy to use.  The  instructions are available online here:   There're some useful tips in the "Advantages of Using The Advance Timing Light" section...

Hope that helps

Jeff
1975 Triumph Trident 750 (New Project)
1980 Yamaha XS1100 (Midnight Special)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Reg'd 1985)
1982 Hesketh V1000 (Pre-Production Engine)

Rob B

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Re: Ignition timing
« Reply #7 on: November 06, 2014, 07:42:27 PM »
That is exactly the one that I've got Jeff.

I wondered whether the wasted spark might have an influence when using it as an advance strobe because in reality, it thinks it has seen two revolutions for each spark when in fact it is seeing a spark on every revolution; then it is trying to work out whether 22 degrees is actually 11 degrees or 22 degrees. Or am I over-complicating things?

RB

RB

1980 Jota - 1982 V1000 - 1985 SFC 1000
1993 907IE - 1995 Daytona Super III
1960 Perplexed Wife

Miti

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Re: Ignition timing
« Reply #8 on: November 16, 2014, 11:36:52 AM »
You're over-complicating things slightly.  The wasted spark will appear 90o after the "T" mark for the cyl you're trying to time and might illuminate the rotor as a "ghost".

I just pre-set the strobe to 22o and, with the sensor clamp on #1 cyl HT lead, adjusted the trigger plate so that the stator "T" mark lined up with the rotor index at the appropriate RPM.

This kind of strobe is also very useful for drawing the ignition curve of your actual bike/system.  With the bike at any given speed, just adjust the strobe so that the T and Index marks line up.  The reading on the strobe is the advance at that specific RPM.  If you measure and record at 250 or 500 rpm increments, you can draw the dynamic curve from idle or static advance, right though to full advance.  It would look somethin like this: (MS Excel chart converted to .jpg image)

PLEASE NOTE THAT THIS IMAGE IS AN EXAMPLE ONLY. IT IS NOT A REFERENCE TABLE!!



NOT true data - just a mock-up given 22 and 34 degrees as min and max figures

Don't forget that perspex cover though.  ;D

Jeff
« Last Edit: November 18, 2014, 09:01:08 PM by Miti »
1975 Triumph Trident 750 (New Project)
1980 Yamaha XS1100 (Midnight Special)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Reg'd 1985)
1982 Hesketh V1000 (Pre-Production Engine)

Miti

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Re: Ignition timing
« Reply #9 on: November 16, 2014, 11:42:22 AM »

One thing all should check is that the marks on the alternator are correct by finding TDC and checking the mark, then you should have two other marks at 22 and 34 degrees which you can check with a degree disc.


So, is full advance supposed to be 34o at 3,500 rpm..?  I think I've got mine set to 22o, which might explain the poor mpg..

Jeff
1975 Triumph Trident 750 (New Project)
1980 Yamaha XS1100 (Midnight Special)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Reg'd 1985)
1982 Hesketh V1000 (Pre-Production Engine)

MICK

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Re: Ignition timing
« Reply #10 on: November 16, 2014, 06:14:44 PM »
Hi Jeff,
Your spreadsheet is a bit out
The clue is in the name Advance "curve"
Full advance is 34 degrees
Advance curve flattens out but does not stop advancing as information already provided.
So 34 degrees at whatever you like to rev the engine to but anything over 6000 rpm wear a crash hat because the valves have lost their way and might want to get there own back.
 8)

Miti

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Re: Ignition timing
« Reply #11 on: November 16, 2014, 09:55:24 PM »
Thanks Mick;

I think you may have missed my small rider:

Quote
NOT true data - just a mock-up given 22 and 34 degrees as min and max figures

My figures are albeit completely fictitious - just intended to give an indcation of what such a chart might look like...

Once I've got my perspex cover sorted, I'll re-time the ignition, 'cos I'm sure I set it as 22o at 3,500 rpm (I gave up then as most of the engine's oil was in my hair..!!)  :o

I think I have 0.8mm as the air gap on the trigger coil/rotor gap... Worth taking down to 0.5mm for easier starting..?  I'll use that 6,000 rpm limit for the timing advance as I know I've revved the poor ol' bugger harder than that (earplugs certainly help). ;)

Jeff
1975 Triumph Trident 750 (New Project)
1980 Yamaha XS1100 (Midnight Special)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Reg'd 1985)
1982 Hesketh V1000 (Pre-Production Engine)

MICK

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Re: Ignition timing
« Reply #12 on: November 17, 2014, 10:32:39 AM »
Hi Jeff
Don't take this the wrong way as I think you are doing a great job but if you post information it needs to be as accurate as possible so not to mislead.
If you look at the workshop manual you get the figures ( sorry I cannot paste it across ) for your graph and then if you have a go at a curve make sure its progressive to be more representative then use your small rider to inform anyone of the source.
The manual gives a reluctor air gap of 0.25mm
The only thing to watch is the reluctor shaft being supported by the outer cover will change the setting when fitted which is impossible to check ;-(
Basically get it as close as you can without the rotor hitting the magnets. 
I am sure that Andy Smith had a copy of the Rita advance curve to use as a  benchmark against my Gill one or you could have a go at creating one with your strobe.
Only point on the curve you don,t have and I can remember is at startup which depends on starter cranking speed of about 800 rpm is about 12 degrees advance.
The Gill one is about 2 degrees for a kinder start.
« Last Edit: November 17, 2014, 10:36:38 AM by MICK »

Miti

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Re: Ignition timing
« Reply #13 on: November 17, 2014, 07:01:06 PM »
I hear you Mick...

I've checked both the Workshop Manual and the Owner's Manual for data... The ignition advance is spec'd as 34o at 5,000 rpm, but I can't find anything that would povide the data for an ignition curve...  Do you have any details of the Rita curve..?  I'd happily amend my fictitious graph with correct data, d it'll be the weekand (at the earliest) before I can actually get the data from my own bike.

And, of course, you're right about the 0.25mm air gap on the reluctor... I think I was cross-confusing specs from my XS1100.  I'll cease and desist from working from my poor memory...

Jeff
« Last Edit: November 17, 2014, 07:40:11 PM by Miti »
1975 Triumph Trident 750 (New Project)
1980 Yamaha XS1100 (Midnight Special)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Reg'd 1985)
1982 Hesketh V1000 (Pre-Production Engine)

MICK

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Re: Ignition timing
« Reply #14 on: November 18, 2014, 01:15:34 PM »
Jeff,
All the Hesketh information went to Paul so its down to memory which believe me is worse than yours.
As a stab at it you have three points which you can plot which are
800 rpm gives 12 degrees advance
3000 rpm gives 22 deg
5000 gives 34 deg

If you can see the mark through the oil at 6000 it will not be far off 34 degrees.
Obviously set the air gap before you do your curve.
The curve shows that if you fire the engine at zero revs the thing would go backwards, ring any bells???

for bells read sprag :-\
« Last Edit: November 18, 2014, 01:29:40 PM by MICK »